Tech-dat/Interface-dat/K-line-dat/K-line-dat.md
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+# K-line-dat
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+- [[CAN-dat]] - [[K-line-dat]] - [[OBD-dat]]
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+## ISO 9141-2 (K-Line) Protocol Overview
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+**ISO 9141-2** is a diagnostic communication protocol primarily used in European and Asian vehicles manufactured between the late 1990s and the mid-2000s. It is the "language" used by an OBD-II scanner to talk to the Engine Control Unit (ECU).
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+### 1. Physical Layer & Pins
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+The protocol relies on a single-wire or dual-wire serial bus found on the standard 16-pin OBD-II connector:
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+* **K-Line (Pin 7):** The bidirectional line used for all data exchange (queries and responses).
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+* **L-Line (Pin 15):** An optional unidirectional line used only for "waking up" the system in older implementations.
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+---
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+### 2. Key Technical Specifications
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+* **Signaling:** Asynchronous serial communication (UART).
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+* **Voltage Levels:** Based on the vehicle battery (0V for Logic Low, 12V for Logic High).
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+* **Baud Rate:** Usually fixed at **10.4 kbps**.
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+* **Initialization:** Requires a specific "5-baud init" (very slow pulse) or a "Fast Init" sequence to establish a handshake before data flows.
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+
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+---
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+### 3. Comparison with Modern CAN Bus
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+| Feature | ISO 9141-2 (K-Line) | ISO 15765 (CAN Bus) |
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+| :--------------- | :------------------------------ | :----------------------- |
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+| **Data Speed** | 10.4 kbps | 500 kbps |
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+| **Architecture** | Master-Slave (Request/Response) | Multi-Master (Broadcast) |
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+| **Typical Era** | 1996 – 2007 | 2008 – Present |
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+| **Hardware** | Single wire (K) | Twisted pair (High/Low) |
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+
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+---
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+
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+### 4. Implementation for DIY Projects
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+Since you are familiar with **motor drivers** and **IMU sensors**, you can think of the K-Line as a standard UART signal shifted to 12V.
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+If you wanted to interface a 3.3V microcontroller (like an ESP32) with a car's K-Line, you cannot connect them directly. You would need a **Level Shifter** or a dedicated K-Line transceiver chip (such as the **L9637D** or **MC33660**) to handle the 12V swings without frying your MCU.
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Tech-dat/Interface-dat/OBD-dat/OBD-dat.md
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-# OBD-dat
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-OBD stands for On-Board Diagnostics. It's a system in modern vehicles that monitors the engine and other vehicle systems. When it detects a problem, it turns on the "check engine" or "service engine soon" light on your dashboard and stores a diagnostic trouble code (DTC) that identifies the issue. This helps technicians diagnose and repair problems more easily.
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-## OBD-II Pinout (SAE J1962 Connector)
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-| Pin | Description |
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-| --- | --------------------------------- |
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-| 1 | Manufacturer specific |
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-| 2 | SAE J1850 Bus+ (PWM/VPW) |
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-| 3 | Manufacturer specific |
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-| 4 | Chassis Ground |
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-| 5 | Signal Ground |
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-| 6 | CAN High (ISO 15765-4) |
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-| 7 | K-Line (ISO 9141-2 / ISO 14230-4) |
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-| 8 | Manufacturer specific |
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-| 9 | Manufacturer specific |
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-| 10 | SAE J1850 Bus- (PWM only) |
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-| 11 | Manufacturer specific |
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-| 12 | Manufacturer specific |
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-| 13 | Manufacturer specific |
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-| 14 | CAN Low (ISO 15765-4) |
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-| 15 | L-Line (ISO 9141-2 / ISO 14230-4) |
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-| 16 | Battery Voltage (+12V) |
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-
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-## the pins in the OBD-II connector related to J1850 are:
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-Pin 2 (SAE J1850 Bus+): Carries the signal for both PWM and VPW protocols.
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-Pin 10 (SAE J1850 Bus-): Used only for the PWM protocol (Ford).
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-## K-line and L-line
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-The K-Line (Pin 7) and L-Line (Pin 15) are communication lines used by the ISO 9141-2 and ISO 14230-4 (KWP2000) diagnostic protocols. These protocols were common in European, Asian, and some Chrysler vehicles before CAN bus became standard.
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-- K-Line (Pin 7): This is the primary bidirectional serial communication line. Diagnostic tools use this line to send requests to and receive data from the vehicle's electronic control units (ECUs).
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-- L-Line (Pin 15): This is an optional unidirectional line primarily used for initialization or "waking up" the ECUs before communication starts on the K-Line. Not all vehicles using K-Line implement or require the L-Line, especially those using the later KWP2000 protocol.
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-In essence:
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-- K-Line: Does the main talking (sending and receiving data).
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-- L-Line: Sometimes used to start the conversation (initialization).
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-## ref
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-- [[CAN-dat]] - [[SAEJ1850-dat]]
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Tech-dat/Interface-dat/can-dat/can-dat.md
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legacy wiki page - https://w.electrodragon.com/w/Category:CAN
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+- [[CAN-dat]] - [[K-line-dat]] - [[OBD-dat]]
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+- [[ECU-dat]]
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+
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## Chip
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- TI ISO1050DUBR
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app-dat/OBD-dat/OBD-dat.md
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# OBD-dat
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-https://github.com/Edragon/OBD == Repository unavailable due to DMCA takedown.
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+https://github.com/Edragon/OBD == Repository unavailable due to DMCA takedown.
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+![](2026-03-04-18-29-25.png)
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+![](2026-03-04-18-29-33.png)
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+![](2026-03-04-18-30-04.png)
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+- [[CAN-dat]] - [[K-line-dat]] - [[OBD-dat]]
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+- ELM327
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+- scanmaster ELM
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+![](2026-03-04-18-37-52.png)
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+OBD-II Pinout (SAE J1962 Connector)
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+| PIN | DESCRIPTION | |
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+| --- | ----------------- | ----- |
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+| 1 | `Vendor Option` | |
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+| 2 | J1850 Bus + | |
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+| 3 | `Vendor Option` | |
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+| 4 | Chassis Ground | Power |
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+| 5 | Signal Ground | Power |
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+| 6 | CAN (J-2234) High | |
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+| 7 | ISO 9141-2K-Line | |
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+| 8 | `Vendor Option` | |
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+| 9 | `Vendor Option` | |
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+| 10 | J1850 BUS | |
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+| 11 | `Vendor Option` | |
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+| 12 | `Vendor Option` | |
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+| 13 | `Vendor Option` | |
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+| 14 | CAN (J-2234) Low | |
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+| 15 | ISO9141-2Low | |
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+| 16 | Battery Power | Power |
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+OBD stands for On-Board Diagnostics. It's a system in modern vehicles that monitors the engine and other vehicle systems. When it detects a problem, it turns on the "check engine" or "service engine soon" light on your dashboard and stores a diagnostic trouble code (DTC) that identifies the issue. This helps technicians diagnose and repair problems more easily.
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+## the pins in the OBD-II connector related to J1850 are:
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+- [[J1850-dat]] - [[SAEJ1850-dat]]
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+Pin 2 (SAE J1850 Bus+): Carries the signal for both PWM and VPW protocols.
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+Pin 10 (SAE J1850 Bus-): Used only for the PWM protocol (Ford).
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+## ref
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+- [[CAN-dat]]